CA2010626A1 - Taper thread cutting machine and method - Google Patents
Taper thread cutting machine and methodInfo
- Publication number
- CA2010626A1 CA2010626A1 CA002010626A CA2010626A CA2010626A1 CA 2010626 A1 CA2010626 A1 CA 2010626A1 CA 002010626 A CA002010626 A CA 002010626A CA 2010626 A CA2010626 A CA 2010626A CA 2010626 A1 CA2010626 A1 CA 2010626A1
- Authority
- CA
- Canada
- Prior art keywords
- bar
- set forth
- rod
- head
- projection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
- B23G5/00—Thread-cutting tools; Die-heads
- B23G5/08—Thread-cutting tools; Die-heads with means for adjustment
- B23G5/10—Die-heads
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23G—THREAD CUTTING; WORKING OF SCREWS, BOLT HEADS, OR NUTS, IN CONJUNCTION THEREWITH
- B23G1/00—Thread cutting; Automatic machines specially designed therefor
- B23G1/02—Thread cutting; Automatic machines specially designed therefor on an external or internal cylindrical or conical surface, e.g. on recesses
- B23G1/04—Machines with one working-spindle
- B23G1/06—Machines with one working-spindle specially adapted for making conical screws, e.g. wood-screws
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T408/00—Cutting by use of rotating axially moving tool
- Y10T408/03—Processes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T408/00—Cutting by use of rotating axially moving tool
- Y10T408/16—Cutting by use of rotating axially moving tool with control means energized in response to activator stimulated by condition sensor
- Y10T408/17—Cutting by use of rotating axially moving tool with control means energized in response to activator stimulated by condition sensor to control infeed
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T408/00—Cutting by use of rotating axially moving tool
- Y10T408/83—Tool-support with means to move Tool relative to tool-support
- Y10T408/85—Tool-support with means to move Tool relative to tool-support to move radially
- Y10T408/858—Moving means including wedge, screw or cam
- Y10T408/8588—Axially slidable moving-means
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T408/00—Cutting by use of rotating axially moving tool
- Y10T408/83—Tool-support with means to move Tool relative to tool-support
- Y10T408/85—Tool-support with means to move Tool relative to tool-support to move radially
- Y10T408/858—Moving means including wedge, screw or cam
- Y10T408/8588—Axially slidable moving-means
- Y10T408/85892—Screw driven wedge or cam
- Y10T408/85895—Traveling wedge
Abstract
ABSTRACT OF THE DISCLOSURE
A machine for taper threading the end of a bar (21) such as reinforcing bar used in concrete construction utilizes a power operated vice (40) to clamp and feed the bar end axially into a rotary head (42) which contains chaser tooling holders (116-119) which open uniformly on the bar end as the head rotates. The rotary head is axially stationary but contains an axially movable key or linear cam (134) which engages a readily removable transversely extending control rod assembly (127) in turn moving the chaser holders. Axial movement of the power vice and thus the bar end at a controlled axial speed with respect to the rotary speed of the head moves the key to cause the movement of the chaser holders. The chaser holders in addition to supporting the thread cutting chasers (181) also support ahead of the chaser an indexable triangular insert (180) to pre-cone the bar end. To change the set-up of the machine for different bar sizes the control rod is removed and replaced, and a proper cutting speed for the bar is selected by adjusting the RPM of the head through a transmission. The extent of axial movement of the key may also be controlled to optimize the cycle time of the machine. In this manner all bar sizes may be threaded in a single pass and set-up from bar size to bar size is accomplished quite simply in a short period of time.
A machine for taper threading the end of a bar (21) such as reinforcing bar used in concrete construction utilizes a power operated vice (40) to clamp and feed the bar end axially into a rotary head (42) which contains chaser tooling holders (116-119) which open uniformly on the bar end as the head rotates. The rotary head is axially stationary but contains an axially movable key or linear cam (134) which engages a readily removable transversely extending control rod assembly (127) in turn moving the chaser holders. Axial movement of the power vice and thus the bar end at a controlled axial speed with respect to the rotary speed of the head moves the key to cause the movement of the chaser holders. The chaser holders in addition to supporting the thread cutting chasers (181) also support ahead of the chaser an indexable triangular insert (180) to pre-cone the bar end. To change the set-up of the machine for different bar sizes the control rod is removed and replaced, and a proper cutting speed for the bar is selected by adjusting the RPM of the head through a transmission. The extent of axial movement of the key may also be controlled to optimize the cycle time of the machine. In this manner all bar sizes may be threaded in a single pass and set-up from bar size to bar size is accomplished quite simply in a short period of time.
Description
2~ 0626 Title: TAPE~ THREAD CUTTING MACHINE AND METHOD
DISC LOSU RE
This invention relates generally as indicated to a taper thread cutting machine and method and more particularly to a machine and method for cutting taper threflds on bar ends.
BACKGROllND OF THE lNVENTlON
-Taper thread splices or joints are widely employed on concrete reinforcing bar used in concrete ConStruCtion. One well known suCh bar splice is sold under the trndemark LENTON by Erico Products, Inc. of Solon, Ohio or Erico BV of Tilburg, Netherlands. The splice utilizes a coupler or sleeve having internal taper threads mating with precision taper threaded ends of the bars to form full tension butt splices. Such splices are available for all sizes of reinforcing bar from #3 (lOmm) to #18 (57mm).
The taper threaded bar ends may be prepared on a bar tllreading machine such as shown in U.S. Patent 4,526,496 and also sold under the trademark LENTON. Similar machines may be seen in prior U.S. Patents 4,282,618 and 4,213,722.
The LENTON bflr threader utilized a rotary head with a square opening accom modating four interfitting chaser holders. The head is indexed axially of a fixed bar end. The chaser holders are moved in the head by an axially extending control key or linear cam through a spring held cam block mounted for sliding movement on a transverse rod. The control key in~ludes projecting rollers which engage a ring.
While the machine described above satisfactorily forms precision tapered threads on bar ends, it may require several passes to form the threads on large bar ends. It also requires substantial and fairly complex changes or set-up to switch from one bar size to another. For example, up to four passes may be required for some bar sizes and set-up for a different bar size may require twenty to thirty minutes, and a skilled operator. On some bar sizes the chaser holders, cam blocks and springs have to be changed, and for each bar size the rather inaccessible control key requires changing. Moreover the bar ends usually have to be saw cut or otherwise prepared, rather than simply sheared.
Z0~06z6 The excessive work done by the chasers results in excessive wear and more frequent replacement, which again results in downtime or pro-duction inefficiency.
It would therefore be desirable to have a machine which would thread a bar end in one pass within an optimum cycle time and in which the set-up required for converting the machine from one bar size to another could be shortened and simplified.
SU~ IARY OY THE INVENTION
A m~chine for taper threading the end of a bar such as r einforcing bar used in concrete c~ostruction uti~izes a power operated vice to clamp and feed the bar end axially into R rotary head which contains chaser tooling holders which open uniformly on the bar end as the head rotates. The rotary head is axially stationary but contains an axially movable key or linear cam which engages a read;ly removable transversely extending control rod assembly in turn moving the chaser holders. Axial movement of the power vice and thus the bar end at a controlled axial speed with rèspect to the rotary speed of the head moves the key to cause the movement of the chaser holders. The chaser holders in addition to supporting the thread cutting chasers also support ahead of the chaser an indexable triangular insert to pre-Cone the bar end. To change the set-up of the machine for different bar Sizes the control rod iS removed and replaced, and ~ proper cutting speèd for the b~r is gelected by ~djusting the RPM of the head through a transmission. The extent of axial movement of the key may als~e controlled to optimize the cycle time of the machine. In this manner all bar sizes may be threaded in a single pass and set-up from bar size to bar size is accomplished quite simply in a short period of time.
To the accomplishment of the foregoing and related ends the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.
2~0626 BRIEF DESCRIPTION OF TH~ DRAWINGS
.
In the annexed drawings:
l~igure I is a side elevation of a machine in accordance with the present invention;
Figure 2 is ~ top plan view of the machine Figure 3 is an end elevation of the machine as seen from the left hand side of Figures 1 and 2 Figure 4 is an end elev~tion of the opposite end;
Figure 5 is an enlarged side elevation ~f the rotary machining head illustr~ting at the top the axi~lly movable key or linear cam;
Figure 6 is a tr~tlsaxial section of the head ~s seen from the line 6-6 of Fi~ure 5;
~ igure 7 is a horizontal section of the head seen from the line 7-7 of E~igure 6;
Figure 8 is an end elevation of a tool holder;
Figure 9 is a side elevation of the tool holder;
Figure 10 iS a top plan view of the tool holder:
Figure 11 is a somewhat enl~rged end elev~tion of ~n insert holder which fits in the tool holder;
Figure 12 is ~ top plan view oî the insert holder;
~ igure 13 is ~ section of the insert holder seen from the line 13-13 of Figure 12; nnd ~ igures 14-18 are sequence illustrations illustrating the action of the pre-coning inserts and chasers supported by the tool holders as the bar is moved into the rotary heAd to thread ~ bar end in a single pass.
l:~ETAILED DESCRIPTION OF THE PREFERRED EMBODJMENTS
Referring first to Figures 1-4 there is illustrated a tsper thread cutting rrachine shown generally at 20 for bar ends shown at 21 in Figures 1 and 3. The machine includes a frame having pairs of end legs 23 and 24 and a pair of middle legs 25. The legs support a lower horizontal frame 26. The paired legs 23 and 25 support a horizontal bed frame 27 at a somewhat elevated position with the bed frame extending between the paired legs 23 and vertical frame members 28, which extend from the lower horizontsl ~010626 îrame 26 to elevated frame mem~ers 29, which in tUrn extend between thetop of the frame members 28 and the end frame members 24.
Extending upwardly from the horizontal bed frame 27 are three vertical plates indicated at 32, 33 and 34 which are interconnected by three triangularly arranged horizontally e.Ytending tie rods 35, 36 and 37. The external surfaces of such tie rods are polished and mounted on such tie rods for horizontal movement is a bar vice assembly shown generally at 40 in Figures I and 2, and also a control ring 41. The control ring surrounds rotary machining head 42 which is mounted on spindle 43 journaled at 44 in the plate 33. The opposite end of the spindle 43 extends from worm gear reducer 45 mounted on plate 34. The worm gear of the redu~er is driven by a cog belt 47 trained ~round sheaves 48 and 49, the former driving the worm gear while the latter is driven by speed change gear box 50, which is in turn driven by V-belt 52 trained around sheave 53 from spindle motor 54. The speed change gear box is mounted on a pivoting platform ss, the position of which may be adjusted to provide proper belt tension. The gear box S0 includes a gear shift handle seen at S6.
;~ounted above the worm gear reducer 45 is a reversible variable speed DC motor 60 which drives a right angle gear box 61 which, through shaft coupler 62, rotates ball screw 63 which is journaled as indicated at 64 in plate 33 and by end cap 65 in plate 32. l`he ball screw 63 extends through a b~l nut 67 which is p~rt of the vice assembly 40.
As seen more clearly in Figures 1, 2 and 3 the vice assembly 40 comprises parallel vertical plates 70 and 71. The parallel plates are interconnected by hubs 72, 73 and 74 in which are mounted bushings supporting the vice assembly for linear movement on the rods 35, 36 and 37, respectively. The plates are also connected at each side by transverse frame members 76 and 77 in which is journaled an Acme screw 78 which has left hand threads on one end and right hand threads on the other end. Two jaw members seen at 80 and 81 include internal threads in mesh with the threads of the Acme screw so that rotation of the screw in opposite directions will move the jaw members toward and away from each other.
The portions of the jaw members which engage the bar end 21 are offset below the Acme screw 78.
The Acme screw may be driven by a reversible electric motorseen at 83 mounted on br~,cket 84. As noted in Figure 2 the jaws of the vice assernbly are substantially elongated in the direction of the ~xis of the machine and thus grip the bar 21 over a substantial length. In any event the bar is gripped firmly and held against rotation by the jaws oî the vice assem bly.
The machine ~lso includes a bar stop indicated ~t 86 in Figure l which is mount~d on ~ horizontally extending pivot shaft 87. The bar stop engages the projecting end of the bar 21 as seen at 88 and may be pivoted out of the way by handle 89. When the handle is elevated to the phantom line position seen at 90 in Figure 3 the bar stop movcs to the position seen at 91. As seen in Figure I the bar stop 86 is urged to the left by a compression bu~per material 92 in the event that the bar enters the machine by means of a powered conveyor.
A control ring 41 has secured thereto three hubs 95, 96 and 97 which house bushings which ride on the rods 35, 36 and 37, respectively.
Also connected to the control ring are plungers 98 of spring plunger assemblies 99 and 100 (see Figure 4). Such spring plunger flssemblies, one diametrically on each side, ur~e the control ring 41 to the left as seen in Figure 2 toward the vice assembly 40.
As seen in Figure I the somewh~t elevated bed frame 27 may include a chute 103 designed to funnel chips into bin 104, which at the end of the day or shift may be tilted to the phantom line position 105 so that it may be shoveled out.
Mounted on the DC motor 60 driving the ball screw 63 is a pulse generator indi~ated at 108 which reads the speed of the motor 60 and thus the RPM of the ball serew. Mounted on the worm gear reducer is an eneoder 109 seen in Figure 4 which measures the RP~ of the spindle 43 and thus the machining head 42. The encoder los acts AS a master while the pulse generator acts as a slave. A closed loop velocity controller uses these signals to direct the DC motor to follow at the proper speed ratio. Thus the controller wh;ch reads the RPM of the spindle translates that to a proper RPM for the ball screw and provides proper lead for the thread being formed 201~)62~
by closely controlling the axial movement of the bar with respect to the rotary speed of the spindle or machining head.
Referring now to Figures 5, 6 and 7 there is illustrated the rot~ry m~chining head 42 which includes a square recess 112 which is open to the f~ce 113 of tl~e head. The cutting head is mounted on the end of the spindle which extends from the opposite face 114. The recess includes four planar interior walls with opposite wa~ls being parallel to each other and each wall being parallel to the axis of the machine or spindle. Mounted within the recess known as the cutting square are four tool holders seen at 116, 117, 118 and 119 which interfit not only with the walLs of the cutting square but also with each other so that opening or clos;ng movement of one concurrently opens or closes al~.
One of the tool holders indicated at llg is provided with a slot 120 in which is positioned a lateral extension 121 of control block 122. The control block is a projection of the tool holder and is positioned in radially extending slot 125 and is internPlly threaded to receive the external threads seen at 126 on control rod 127. The control rod includes a stop shoulder 128 abutting against the control block 122.
The control rod 127 also includes an annular stop shoulder 130.
The control rod extends through and the annular stop shoulder abuts against a thrust block 131 which includes an upwardly extending projection be~ring against line~r cam surface 133 of control key 134. The control key is mounted for movement axially of the he~d in slot 13S.
- Surrounding the control rod on the opposite side of the annular stop shoulder 130 is a compression spring 137 which extends between the annul~r stop shoulder and threaded bushing 138. The control rod extends through transverse passage 140 in the rotary head and the threaded bushing is threaded into the outer end of the passMge. The oppositè end of the control rod extends through a smaller aligned transVerSe passage 141. The transverse passage 140 opens laterally of the rotary head through the slightly enlarged opening 142. As indicated, the projecting end of the threaded bushing may be provided with a transverse slot seen at 143 in Figure 5 while the projecting end of the control rod msy be provided with flats seen at 144.
ZO~ Z6 In this manner a suitable tool on a speed wrench may readily remove or replace both.
It can now be seen that the distance between the annular stop shoulder 130 and the stop shoulder 128 is fixed by the control rod. This dimension then controls the spacing between the linear cam surface and the control block or projection extending from one of the tool holders. ~or each bar size there will be ~ different control rod with a different dimension between the two stop shoulders. To change control rods the thre~ded bushing is removed simply by unscrewing it. Then the control rod is unscrewed from the projection or control block 122 and replaced by a control rod having a dlfferent dimension. The compression spring is then seated over the annular stop shoulder and the threaded bushing is replaced.
Although it will be appreciated that the spacing may be changed by simply rotating the control rod in the projection, it is preferred to provide two set stop shoulders so that the control rod is inserted to a stop position thus avoiding care or skill in changing the machine from one bar size to another.
As seen in Figure 5 the axially movable control key is provided with two cam rollers 147 and 148 which are positioned on opposite sides of the control ring 41. The control key may also include threaded tapped holes seen at 150 and 151 providing a~ternate locations for the roller 147 to shorten the stroke of the machine and thus provide optimum cycle time depending upon the bar size being threaded.
Referring now to Figures 8, 9 and 10 there is illustrated a chaser or tool holder 119 in accordance with the present invention. l`;,e tool holder comprises a block which includes right angled planar exterior surfaces 155 and 156 which cooperate with the internal walls of the cutting square and angled walls 157 and 158 which cooperate with the walls 158 and i57, respectively, on adjoining blocks. The wall 156 may be provided with the slot 120 receiving the projection or control block. The block is relieved as indicated at 160 and is provided with an angled shoulder 161 to receive the chaser.
The front of the tool holder or that side which extends toward the face 113 of the rotary head includes a recess 164 in which is positioned an ;20~06Z~
insert holder 165 shown in more detail in ~igures 11 12 and 13. Each chaser is held to the tool holder by a suitable pin f~stener extending through the chaser and into the hole indicated at 167 while the insert holder is held to the holder by a suitable fQstener extending through hole 168 in the insert holder and thre~ded into the holder in ~ suitable tapped hole the axis of whicl? is shown at 169 in Figure lo.
The insert holder comprises a generally rectangular block which is relieved as indicflted at 171. The relieved end of the block is provided with~ triangular seat 172 which is at a slight angle to the end face of the insert holder. The seat is provided with fl tapped hole indicated at 173 so that a triangular roughing or pre-coning Cutting tool m~y be secured to the seatt When the insert holder is positioned in the tool holder the surfaces 175 and 176 seen in Figure 12 will abut againSt the surfaces 177 and 178 of the recess of the tool hol~er as seen in Figure 10.
In Figures 14-18 there is illustrated the triangular indexable pre-coning insert 180 mounted in the insert holder 165 and there is also illustrated a chaser 181 with both the insert holder and chaser being mounted in the tool holder 119.
~ n operation the vice assembly moves the bar end 21 to the right as seen in Figures 14-18 and as the vice assembly moves the bar end the vice asse nbly picks up the control ring 41 which also moves to the right in turn engflging the cam roller 148 moving the control key 134 axially in turn to move the tool holders.
As seen in Figure 14 the bar- end 21 which is unsawcut or unprepared otherwise is entering the cutting head as the cutting head rot~tes. The bar is initially engaged by the edge of the triangular pre-coning cutting tool 180. As seen in Figure 15 the indexable cutting insert 180 is beginning to cut the bar end or to pre-cone the bar end.
In Figure 16 the chasers have begun to engage the pr~coned bar end while the triangular insert is still cutting or pre-coning the bar end.
In Figure 17 the chaser is approaching the end of the threading cycle and the triangular cutting tool has disengaged the work. In Figure 18 at the end of the cycle the thrust block reaches the pop off ramp 183 of the Z0:10626 _g_ key seen in Figure 7 and the ch~sers cleRr the end of the b~r to permit the withdr~3wal of the b~r end. As soon ~s the pop off o~cUrs the cycle iS
completed and the vice withdr~ws the bar end with the spring plungers retracting the control ring 41 by engaging the opposite cam roller which as indicated may be set positionally to obtain an optimum cycle for the machine depending upon the bar size being threaded. In the ~bove described manner the machine will thre~d any bar si~e in a single pass and the only set-up requirement other than adjustments on the control panel required by the operator is to replace the control rod with a control rod having a different shoulder-to-shoulder dimension flnd, for some size bars, to change the speed of the transmission through gear shift handle 56.
With the triangular pre-coning insert there is avoided multiple passes for larger bars when there is lots of material to be removed. This significantly shortens the cycle time on larger size bars and moreover provides a significant increase in the life of the chaser. When the tip or the edge of the pre-coning insert becomes dull it may simply be indexed to present another tip or cutting edge to the work.
The total machine then comprises the machine illustrated and a complete set of control rods, one for each size of bar to be threaded.
Although the invention has been shown and described with respect to certain preferred embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon thè
reading and understanding of this specification. The present invention includes all such equivale:lt alterations and modifications, and is limited only by the scope of the following claims.
DISC LOSU RE
This invention relates generally as indicated to a taper thread cutting machine and method and more particularly to a machine and method for cutting taper threflds on bar ends.
BACKGROllND OF THE lNVENTlON
-Taper thread splices or joints are widely employed on concrete reinforcing bar used in concrete ConStruCtion. One well known suCh bar splice is sold under the trndemark LENTON by Erico Products, Inc. of Solon, Ohio or Erico BV of Tilburg, Netherlands. The splice utilizes a coupler or sleeve having internal taper threads mating with precision taper threaded ends of the bars to form full tension butt splices. Such splices are available for all sizes of reinforcing bar from #3 (lOmm) to #18 (57mm).
The taper threaded bar ends may be prepared on a bar tllreading machine such as shown in U.S. Patent 4,526,496 and also sold under the trademark LENTON. Similar machines may be seen in prior U.S. Patents 4,282,618 and 4,213,722.
The LENTON bflr threader utilized a rotary head with a square opening accom modating four interfitting chaser holders. The head is indexed axially of a fixed bar end. The chaser holders are moved in the head by an axially extending control key or linear cam through a spring held cam block mounted for sliding movement on a transverse rod. The control key in~ludes projecting rollers which engage a ring.
While the machine described above satisfactorily forms precision tapered threads on bar ends, it may require several passes to form the threads on large bar ends. It also requires substantial and fairly complex changes or set-up to switch from one bar size to another. For example, up to four passes may be required for some bar sizes and set-up for a different bar size may require twenty to thirty minutes, and a skilled operator. On some bar sizes the chaser holders, cam blocks and springs have to be changed, and for each bar size the rather inaccessible control key requires changing. Moreover the bar ends usually have to be saw cut or otherwise prepared, rather than simply sheared.
Z0~06z6 The excessive work done by the chasers results in excessive wear and more frequent replacement, which again results in downtime or pro-duction inefficiency.
It would therefore be desirable to have a machine which would thread a bar end in one pass within an optimum cycle time and in which the set-up required for converting the machine from one bar size to another could be shortened and simplified.
SU~ IARY OY THE INVENTION
A m~chine for taper threading the end of a bar such as r einforcing bar used in concrete c~ostruction uti~izes a power operated vice to clamp and feed the bar end axially into R rotary head which contains chaser tooling holders which open uniformly on the bar end as the head rotates. The rotary head is axially stationary but contains an axially movable key or linear cam which engages a read;ly removable transversely extending control rod assembly in turn moving the chaser holders. Axial movement of the power vice and thus the bar end at a controlled axial speed with rèspect to the rotary speed of the head moves the key to cause the movement of the chaser holders. The chaser holders in addition to supporting the thread cutting chasers also support ahead of the chaser an indexable triangular insert to pre-Cone the bar end. To change the set-up of the machine for different bar Sizes the control rod iS removed and replaced, and ~ proper cutting speèd for the b~r is gelected by ~djusting the RPM of the head through a transmission. The extent of axial movement of the key may als~e controlled to optimize the cycle time of the machine. In this manner all bar sizes may be threaded in a single pass and set-up from bar size to bar size is accomplished quite simply in a short period of time.
To the accomplishment of the foregoing and related ends the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.
2~0626 BRIEF DESCRIPTION OF TH~ DRAWINGS
.
In the annexed drawings:
l~igure I is a side elevation of a machine in accordance with the present invention;
Figure 2 is ~ top plan view of the machine Figure 3 is an end elevation of the machine as seen from the left hand side of Figures 1 and 2 Figure 4 is an end elev~tion of the opposite end;
Figure 5 is an enlarged side elevation ~f the rotary machining head illustr~ting at the top the axi~lly movable key or linear cam;
Figure 6 is a tr~tlsaxial section of the head ~s seen from the line 6-6 of Fi~ure 5;
~ igure 7 is a horizontal section of the head seen from the line 7-7 of E~igure 6;
Figure 8 is an end elevation of a tool holder;
Figure 9 is a side elevation of the tool holder;
Figure 10 iS a top plan view of the tool holder:
Figure 11 is a somewhat enl~rged end elev~tion of ~n insert holder which fits in the tool holder;
Figure 12 is ~ top plan view oî the insert holder;
~ igure 13 is ~ section of the insert holder seen from the line 13-13 of Figure 12; nnd ~ igures 14-18 are sequence illustrations illustrating the action of the pre-coning inserts and chasers supported by the tool holders as the bar is moved into the rotary heAd to thread ~ bar end in a single pass.
l:~ETAILED DESCRIPTION OF THE PREFERRED EMBODJMENTS
Referring first to Figures 1-4 there is illustrated a tsper thread cutting rrachine shown generally at 20 for bar ends shown at 21 in Figures 1 and 3. The machine includes a frame having pairs of end legs 23 and 24 and a pair of middle legs 25. The legs support a lower horizontal frame 26. The paired legs 23 and 25 support a horizontal bed frame 27 at a somewhat elevated position with the bed frame extending between the paired legs 23 and vertical frame members 28, which extend from the lower horizontsl ~010626 îrame 26 to elevated frame mem~ers 29, which in tUrn extend between thetop of the frame members 28 and the end frame members 24.
Extending upwardly from the horizontal bed frame 27 are three vertical plates indicated at 32, 33 and 34 which are interconnected by three triangularly arranged horizontally e.Ytending tie rods 35, 36 and 37. The external surfaces of such tie rods are polished and mounted on such tie rods for horizontal movement is a bar vice assembly shown generally at 40 in Figures I and 2, and also a control ring 41. The control ring surrounds rotary machining head 42 which is mounted on spindle 43 journaled at 44 in the plate 33. The opposite end of the spindle 43 extends from worm gear reducer 45 mounted on plate 34. The worm gear of the redu~er is driven by a cog belt 47 trained ~round sheaves 48 and 49, the former driving the worm gear while the latter is driven by speed change gear box 50, which is in turn driven by V-belt 52 trained around sheave 53 from spindle motor 54. The speed change gear box is mounted on a pivoting platform ss, the position of which may be adjusted to provide proper belt tension. The gear box S0 includes a gear shift handle seen at S6.
;~ounted above the worm gear reducer 45 is a reversible variable speed DC motor 60 which drives a right angle gear box 61 which, through shaft coupler 62, rotates ball screw 63 which is journaled as indicated at 64 in plate 33 and by end cap 65 in plate 32. l`he ball screw 63 extends through a b~l nut 67 which is p~rt of the vice assembly 40.
As seen more clearly in Figures 1, 2 and 3 the vice assembly 40 comprises parallel vertical plates 70 and 71. The parallel plates are interconnected by hubs 72, 73 and 74 in which are mounted bushings supporting the vice assembly for linear movement on the rods 35, 36 and 37, respectively. The plates are also connected at each side by transverse frame members 76 and 77 in which is journaled an Acme screw 78 which has left hand threads on one end and right hand threads on the other end. Two jaw members seen at 80 and 81 include internal threads in mesh with the threads of the Acme screw so that rotation of the screw in opposite directions will move the jaw members toward and away from each other.
The portions of the jaw members which engage the bar end 21 are offset below the Acme screw 78.
The Acme screw may be driven by a reversible electric motorseen at 83 mounted on br~,cket 84. As noted in Figure 2 the jaws of the vice assernbly are substantially elongated in the direction of the ~xis of the machine and thus grip the bar 21 over a substantial length. In any event the bar is gripped firmly and held against rotation by the jaws oî the vice assem bly.
The machine ~lso includes a bar stop indicated ~t 86 in Figure l which is mount~d on ~ horizontally extending pivot shaft 87. The bar stop engages the projecting end of the bar 21 as seen at 88 and may be pivoted out of the way by handle 89. When the handle is elevated to the phantom line position seen at 90 in Figure 3 the bar stop movcs to the position seen at 91. As seen in Figure I the bar stop 86 is urged to the left by a compression bu~per material 92 in the event that the bar enters the machine by means of a powered conveyor.
A control ring 41 has secured thereto three hubs 95, 96 and 97 which house bushings which ride on the rods 35, 36 and 37, respectively.
Also connected to the control ring are plungers 98 of spring plunger assemblies 99 and 100 (see Figure 4). Such spring plunger flssemblies, one diametrically on each side, ur~e the control ring 41 to the left as seen in Figure 2 toward the vice assembly 40.
As seen in Figure I the somewh~t elevated bed frame 27 may include a chute 103 designed to funnel chips into bin 104, which at the end of the day or shift may be tilted to the phantom line position 105 so that it may be shoveled out.
Mounted on the DC motor 60 driving the ball screw 63 is a pulse generator indi~ated at 108 which reads the speed of the motor 60 and thus the RPM of the ball serew. Mounted on the worm gear reducer is an eneoder 109 seen in Figure 4 which measures the RP~ of the spindle 43 and thus the machining head 42. The encoder los acts AS a master while the pulse generator acts as a slave. A closed loop velocity controller uses these signals to direct the DC motor to follow at the proper speed ratio. Thus the controller wh;ch reads the RPM of the spindle translates that to a proper RPM for the ball screw and provides proper lead for the thread being formed 201~)62~
by closely controlling the axial movement of the bar with respect to the rotary speed of the spindle or machining head.
Referring now to Figures 5, 6 and 7 there is illustrated the rot~ry m~chining head 42 which includes a square recess 112 which is open to the f~ce 113 of tl~e head. The cutting head is mounted on the end of the spindle which extends from the opposite face 114. The recess includes four planar interior walls with opposite wa~ls being parallel to each other and each wall being parallel to the axis of the machine or spindle. Mounted within the recess known as the cutting square are four tool holders seen at 116, 117, 118 and 119 which interfit not only with the walLs of the cutting square but also with each other so that opening or clos;ng movement of one concurrently opens or closes al~.
One of the tool holders indicated at llg is provided with a slot 120 in which is positioned a lateral extension 121 of control block 122. The control block is a projection of the tool holder and is positioned in radially extending slot 125 and is internPlly threaded to receive the external threads seen at 126 on control rod 127. The control rod includes a stop shoulder 128 abutting against the control block 122.
The control rod 127 also includes an annular stop shoulder 130.
The control rod extends through and the annular stop shoulder abuts against a thrust block 131 which includes an upwardly extending projection be~ring against line~r cam surface 133 of control key 134. The control key is mounted for movement axially of the he~d in slot 13S.
- Surrounding the control rod on the opposite side of the annular stop shoulder 130 is a compression spring 137 which extends between the annul~r stop shoulder and threaded bushing 138. The control rod extends through transverse passage 140 in the rotary head and the threaded bushing is threaded into the outer end of the passMge. The oppositè end of the control rod extends through a smaller aligned transVerSe passage 141. The transverse passage 140 opens laterally of the rotary head through the slightly enlarged opening 142. As indicated, the projecting end of the threaded bushing may be provided with a transverse slot seen at 143 in Figure 5 while the projecting end of the control rod msy be provided with flats seen at 144.
ZO~ Z6 In this manner a suitable tool on a speed wrench may readily remove or replace both.
It can now be seen that the distance between the annular stop shoulder 130 and the stop shoulder 128 is fixed by the control rod. This dimension then controls the spacing between the linear cam surface and the control block or projection extending from one of the tool holders. ~or each bar size there will be ~ different control rod with a different dimension between the two stop shoulders. To change control rods the thre~ded bushing is removed simply by unscrewing it. Then the control rod is unscrewed from the projection or control block 122 and replaced by a control rod having a dlfferent dimension. The compression spring is then seated over the annular stop shoulder and the threaded bushing is replaced.
Although it will be appreciated that the spacing may be changed by simply rotating the control rod in the projection, it is preferred to provide two set stop shoulders so that the control rod is inserted to a stop position thus avoiding care or skill in changing the machine from one bar size to another.
As seen in Figure 5 the axially movable control key is provided with two cam rollers 147 and 148 which are positioned on opposite sides of the control ring 41. The control key may also include threaded tapped holes seen at 150 and 151 providing a~ternate locations for the roller 147 to shorten the stroke of the machine and thus provide optimum cycle time depending upon the bar size being threaded.
Referring now to Figures 8, 9 and 10 there is illustrated a chaser or tool holder 119 in accordance with the present invention. l`;,e tool holder comprises a block which includes right angled planar exterior surfaces 155 and 156 which cooperate with the internal walls of the cutting square and angled walls 157 and 158 which cooperate with the walls 158 and i57, respectively, on adjoining blocks. The wall 156 may be provided with the slot 120 receiving the projection or control block. The block is relieved as indicated at 160 and is provided with an angled shoulder 161 to receive the chaser.
The front of the tool holder or that side which extends toward the face 113 of the rotary head includes a recess 164 in which is positioned an ;20~06Z~
insert holder 165 shown in more detail in ~igures 11 12 and 13. Each chaser is held to the tool holder by a suitable pin f~stener extending through the chaser and into the hole indicated at 167 while the insert holder is held to the holder by a suitable fQstener extending through hole 168 in the insert holder and thre~ded into the holder in ~ suitable tapped hole the axis of whicl? is shown at 169 in Figure lo.
The insert holder comprises a generally rectangular block which is relieved as indicflted at 171. The relieved end of the block is provided with~ triangular seat 172 which is at a slight angle to the end face of the insert holder. The seat is provided with fl tapped hole indicated at 173 so that a triangular roughing or pre-coning Cutting tool m~y be secured to the seatt When the insert holder is positioned in the tool holder the surfaces 175 and 176 seen in Figure 12 will abut againSt the surfaces 177 and 178 of the recess of the tool hol~er as seen in Figure 10.
In Figures 14-18 there is illustrated the triangular indexable pre-coning insert 180 mounted in the insert holder 165 and there is also illustrated a chaser 181 with both the insert holder and chaser being mounted in the tool holder 119.
~ n operation the vice assembly moves the bar end 21 to the right as seen in Figures 14-18 and as the vice assembly moves the bar end the vice asse nbly picks up the control ring 41 which also moves to the right in turn engflging the cam roller 148 moving the control key 134 axially in turn to move the tool holders.
As seen in Figure 14 the bar- end 21 which is unsawcut or unprepared otherwise is entering the cutting head as the cutting head rot~tes. The bar is initially engaged by the edge of the triangular pre-coning cutting tool 180. As seen in Figure 15 the indexable cutting insert 180 is beginning to cut the bar end or to pre-cone the bar end.
In Figure 16 the chasers have begun to engage the pr~coned bar end while the triangular insert is still cutting or pre-coning the bar end.
In Figure 17 the chaser is approaching the end of the threading cycle and the triangular cutting tool has disengaged the work. In Figure 18 at the end of the cycle the thrust block reaches the pop off ramp 183 of the Z0:10626 _g_ key seen in Figure 7 and the ch~sers cleRr the end of the b~r to permit the withdr~3wal of the b~r end. As soon ~s the pop off o~cUrs the cycle iS
completed and the vice withdr~ws the bar end with the spring plungers retracting the control ring 41 by engaging the opposite cam roller which as indicated may be set positionally to obtain an optimum cycle for the machine depending upon the bar size being threaded. In the ~bove described manner the machine will thre~d any bar si~e in a single pass and the only set-up requirement other than adjustments on the control panel required by the operator is to replace the control rod with a control rod having a different shoulder-to-shoulder dimension flnd, for some size bars, to change the speed of the transmission through gear shift handle 56.
With the triangular pre-coning insert there is avoided multiple passes for larger bars when there is lots of material to be removed. This significantly shortens the cycle time on larger size bars and moreover provides a significant increase in the life of the chaser. When the tip or the edge of the pre-coning insert becomes dull it may simply be indexed to present another tip or cutting edge to the work.
The total machine then comprises the machine illustrated and a complete set of control rods, one for each size of bar to be threaded.
Although the invention has been shown and described with respect to certain preferred embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon thè
reading and understanding of this specification. The present invention includes all such equivale:lt alterations and modifications, and is limited only by the scope of the following claims.
Claims (17)
1. In combination a taper threading machine for taper thread-ing the ends of different size workpieces comprising a rotary machining head (42) having a planar wall internal recess, a plurality of tooling holders (116-119) in said recess in engagement with said walls and each other for opening and closing movement, a projection (122) on one of said tooling holders, an axially extending linear cam (134), a thrust block (131) in engagement with said cam, characterized by a set of control means (127) adapted to extend between said projection and thrust block to control the distance therebetween, each control means providing a different such distance, one for each size workpiece.
2. The combination set forth in claim 1 wherein each control means comprises a removable rod extending transversely of the axis of the machining head, and means removably to secure each rod to said projection.
3. The combination set forth in claim 2 wherein said last mentioned means comprises A threaded connection and a projection-rod stop shoulder (128).
4. The combination set forth in claim 3 wherein said rod includes a thrust block stop shoulder (130) adapted to engage said thrust block .
5. The combination set forth in claim 4 wherein the axial dimension between said shoulders along said rod is different for each rod.
6. The combination set forth in claim 5 wherein said thrust block shoulder is annular and said rod extends through said thrust block, and a compression spring (137) seated against said annular shoulder urging said rod against said thrust block and said thrust block in turn against said cam, and spacing said projection the selected dimension.
7. The combination set forth in claim 6 wherein said spring encircles said rod and extends between said annular shoulder and a removable bushing.
8. The combination set forth in claim 7 wherein said rod is mounted in a passage in said rotary head extending transversely of the axis of said head, and said removable bushing is threaded in the end of said passage.
9. The combination set forth in claim 1 including a vice for holding the workpiece, and means to move said vice and thus the workpiece axially into said head.
10. The combination set forth in claim 9 wherein said last mentioned means comprises a rotary screw and nut, and means to read the RPM of the machining head and rotate said rotary screw accordingly.
11. The combination set forth in claim 1 wherein said tooling holders each include removable chasers supported at ~ uniform taper angle, said tooling holders further including a removable insert supporting a cutting tool adapted to pre-cone the work for engagement by said chasers.
12. A machine as set forth in claim 11 wherein said cutting tool is a triangular cutting tool having three cutting edges, and means to remove said triangular cutting tool from said insert to enable indexing of said cutting tool to present a different cutting edge to the work as an edge wears.
13. A set-up process for a taper thread cutting machine for work of different size of the type having a rotary machining head with a planar wall recess accommodating a plurality of tool holders engaged with the walls and each other for opening and closing movement, a projection on one of said holders, and a control rod removably secured to said projection and including a first stop shoulder for engaging a thrust block which in turn engages a linear cam movable axially of said head to close said tool holders uniformly on the work, said control rod having a predetermined dimension from said projection to said shoulder, said dimension being related to the size of the work, the set-up process comprising removing said control rod and replacing said rod with a different shoulder-projection dimension.
14. A process as set forth in claim 13 wherein the selected control rod is threaded into said projection against a second stop shoulder?
and a spring is positioned against said first shoulder to force said first shoulder against said thrust block and to set the position of said projection and thus said tool holders.
and a spring is positioned against said first shoulder to force said first shoulder against said thrust block and to set the position of said projection and thus said tool holders.
15. A process as set forth in claim 14 wherein the selected control rod is positioned in a passage in said machining head extending transversely of the axis of said head, and closing said passage with a threaded bushing to compress said spring against said first shoulder.
16. A process as set forth in claim 15 wherein the work comprises concrete reinforcing bar, and a separate control rod for each size bar.
17. A process as set forth in claim 16 including the step of limiting the axial movement of said linear cam to optimize the cycle time of the machine.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US334,333 | 1981-12-24 | ||
| US07/334,333 US5158404A (en) | 1989-04-07 | 1989-04-07 | Taper thread cutting machine and method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2010626A1 true CA2010626A1 (en) | 1990-10-07 |
Family
ID=23306732
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002010626A Abandoned CA2010626A1 (en) | 1989-04-07 | 1990-02-21 | Taper thread cutting machine and method |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US5158404A (en) |
| EP (1) | EP0391051A3 (en) |
| CA (1) | CA2010626A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9706279D0 (en) * | 1997-03-26 | 1997-05-14 | Robb Stewart | Machining assembly |
| US6877934B2 (en) * | 2002-10-28 | 2005-04-12 | Rem Sales, Inc. | Milling head for thread whirling |
| CN105772831B (en) * | 2016-04-27 | 2018-03-20 | 中铁建工集团有限公司 | Straight thread reinforced bar termination equating device |
| CN106513875B (en) * | 2017-01-12 | 2019-01-22 | 兰州理工大学 | The manual die handle of adjustable steel bar diameter and application method |
| CN113231700B (en) * | 2021-04-29 | 2023-01-24 | 东莞市福华建筑工程有限公司 | Threading machine die teeth mechanism for construction |
| CN113182622A (en) * | 2021-04-30 | 2021-07-30 | 许淑杰 | Automatic internal thread machining device |
Family Cites Families (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA507286A (en) * | 1954-11-16 | N. Bridges George | Stocks and dies, die heads and the like thread cutting tools | |
| USRE23684E (en) * | 1953-07-14 | Machine tool | ||
| US448971A (en) * | 1891-03-24 | Machine for cutting threads on bolts and nuts | ||
| US942200A (en) * | 1908-09-01 | 1909-12-07 | Henry Gautschi | Pipe and rod threader. |
| US2054028A (en) * | 1934-09-13 | 1936-09-08 | William L Benninghoff | Machine for cutting threads |
| US2036821A (en) * | 1935-11-07 | 1936-04-07 | Gen Electric | Machine tool driving system |
| US2219944A (en) * | 1939-10-02 | 1940-10-29 | Oster Mfg Co | Threading and cutting machine |
| US2583094A (en) * | 1948-04-24 | 1952-01-22 | Hill Acme Company | Taper threading machine |
| FR1077378A (en) * | 1953-05-18 | 1954-11-08 | Outil Precy | Improvements to expandable sectors |
| US3074367A (en) * | 1960-05-06 | 1963-01-22 | Singer Mfg Co | Rotary hook for sewing machines |
| CH420800A (en) * | 1964-08-01 | 1966-09-15 | Werkzeugbau Leipzig Veb | Self-opening die stock, especially for hand use |
| US3829920A (en) * | 1973-07-05 | 1974-08-20 | Pipe Machinery Co | Tool head with multiple tools and common oscillatable recede and collapse cam mechanism |
| US4079235A (en) * | 1976-12-27 | 1978-03-14 | Mcdonnell Douglas Corporation | Computer numerically controlled threadcutting machine tool |
| GB2011298B (en) * | 1977-12-27 | 1982-05-12 | Foell Remswerk | Portable thread cutting machine for cutting external threads |
| DE2831718A1 (en) * | 1978-07-19 | 1980-01-31 | Foell Remswerk | THREADING JAW FOR EXTERNAL THREADING MACHINES |
| CH636787A5 (en) * | 1978-12-04 | 1983-06-30 | Max Hetzel | ELECTRONICALLY CONTROLLED THREADING MACHINE. |
| US4526496A (en) * | 1982-06-25 | 1985-07-02 | Erico Products, Inc. | Tapered thread cutting machine |
| US4531866A (en) * | 1982-09-27 | 1985-07-30 | Teledyne Industries, Inc. | Chaser position control |
| US4531867A (en) * | 1984-02-16 | 1985-07-30 | Dexport Tool Company | Cutting tool |
| JPH0757444B2 (en) * | 1985-06-28 | 1995-06-21 | ブラザー工業株式会社 | Screw processing equipment |
| JP2510980B2 (en) * | 1985-10-21 | 1996-06-26 | 株式会社安川電機 | Screw cutting control method |
| EP0332975B1 (en) * | 1988-03-18 | 1992-08-12 | Siemens Aktiengesellschaft | Method for screw thread production on numerical machines |
-
1989
- 1989-04-07 US US07/334,333 patent/US5158404A/en not_active Expired - Fee Related
-
1990
- 1990-02-21 CA CA002010626A patent/CA2010626A1/en not_active Abandoned
- 1990-02-22 EP EP19900103375 patent/EP0391051A3/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| US5158404A (en) | 1992-10-27 |
| EP0391051A3 (en) | 1991-03-27 |
| EP0391051A2 (en) | 1990-10-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |